1. Technical Field
The present invention relates to CMOS (Complementary Metal Oxide Semiconductor) technology, and more specifically, to improvements to CMOS technology.
2. Related Art
In traditional CMOS (Complementary Metal Oxide Semiconductor) technology, the fabrication of a semiconductor transistor comprises (a) forming a gate stack (including a polysilicon gate region on a gate dielectric region) on a semiconductor layer, and (b) forming first and second source/drain (S/D) regions (i) in the semiconductor layer and (ii) aligned with the gate stack. The first and second S/D regions define a channel region in the semiconductor layer and directly beneath the gate dielectric region. As device dimensions continue to shrink (i.e., scaling), the gate dielectric region that electrically insulates the channel region and the polysilicon gate region of the transistor becomes thinner and therefore experiences increasing leakage current due to direct carrier tunneling, resulting in degraded device performance.
As a result, there is a need for methods of forming transistors in which leakage current problem is mitigated.